Voice activity detection (VAD) approaches are important components of speech recognition software and hardware. For example, recognition software constantly scans the audio signal of a microphone searching for voice activity, usually, with a MIPS intensive algorithm. Since the algorithm is constantly running, the power used in this voice detection approach is significant.
Microphones are also disposed in mobile device products such as cellular phones. These customer devices have a standardized interface. If the microphone is not compatible with this interface it cannot be used with the mobile device product.
Many mobile devices products have speech recognition included with the mobile device. However, the power usage of the algorithms are taxing enough to the battery that the feature is often enabled only after the user presses a button or wakes up the device. In order to enable this feature at all times, the power consumption of the overall solution must be small enough to have minimal impact on the total battery life of the device. As mentioned, this has not occurred with existing devices.
Because of the above-mentioned problems, some user dissatisfaction with previous approaches has occurred.
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